"[It's] big news in Canada but big news around the world," Chantelois said. "Not only because he is probably the sexiest politician alive but also because there has never been a leader of a country to walk in a parade, at least not that we know of.”

He said no former Canadian prime minister has taken part in a Toronto Pride parade, either.

Trudeau, who has attended Pride parades in Toronto and Vancouver for years, tweeted that he looked forward to being there again, "this time as PM."

Chantelois said he spoke to Trudeau recently at his office in Ottawa, where he was "very surprised" and "very excited" to hear he would be the first Canadian prime minister to take part.

“It’s a nice way to make history,” Chantelois said.

He said Trudeau also showed a deep understanding and commitment to issues facing the LGBT community in Canada.

"When we met him in his office, he was really serious about talking about trans rights, about equal rights, about immigration, about gay men donating blood," Chantelois said. "All these things are very important topics for him.”

The Toronto Pride Parade takes place July 3.

Ishmael N. Daro is a reporter for BuzzFeed News and is based in Toronto. PGP fingerprint: 5A1D 9099 3497 DA4B